The Republican chairman of a House panel that oversees the U.S. Census Bureau slammed the Obama administration on Tuesday over reports that extensive changes to the agency's annual survey will make it virtually impossible to track how Obamacare has affected Americans.

"The census should not be political," Texas Rep. Blake Farenthold told Newsmax in a statement. The two-term congressman is chairman of the House Oversight Subcommittee on the Federal Workforce, U.S. Postal Service, and the Census.

"These reports do nothing but give more weight to Americans' level of general distrust in the Obama administration, especially after the president's failed promise that 'if you like your health insurance, you can keep it,'" Farenthold said.

The extensive revamping of the bureau's survey, which is to be used in September, was approved by the Office of Management and Budget, The New York Times reports.

"We are expecting much lower numbers just because of the questions and how they are asked," Brett J. O’Hara, chief of the Census Bureau's health statistics operation, told the Times.

The bureau is long considered the authority on health data, the Times reports. The changes seek to improve the survey's accuracy, but bureau officials told the newspaper that the questions are so different that it will be very difficult to compare the results with data from previous years.

The new survey includes a "total revision to health insurance questions" and, in a test last year, produced lower estimates on uninsured Americans, according to an internal report from the bureau quoted by the Times.

As such, the new findings will make it hard for officials to determine what changes in recipients' health-coverage status might have resulted from Obamacare.

"It is likely that the Census Bureau will decide that there is a break in series for the health insurance estimates," another agency report on the changes said. And this "break in trend" will make it very difficult to determine the impact of Obamacare, according to the Times.

The changes include more detailed questions about whether people were offered insurance at work and whether they accepted it, the Times reports. If a worker does not employer coverage, the survey asks why.

Several of the new questions were requested by the Department of Health and Human Services and the White House Council of Economic Advisers, the Times reports.

Formally known as the Bureau of the Census, the agency was created in 1903. Under the Constitution, it is charged with counting the nation's population every 10 years. Between the decades the bureau makes population estimates and projections.

Besides affecting how congressional districts are drawn, census data plays a key role in how more than $400 billion in federal and state funding is allocated every year for such services as public health, education, transportation, and neighborhood improvements.

"Census data influences decisions made from Main Street to Wall Street, in Congress and with the Federal Reserve," Farenthold told Newsmax. "Not to mention, the American people who look to, and trust, the data the government releases on our nation's unemployment, state of our economy, and health insurance coverage."

The Census Bureau operated as an independent entity within the U.S. Commerce Department, answering to the Commerce Secretary, though its director is appointed by the president. The current director is John Thompson.

But that changed in 2009, when President Barack Obama moved the bureau under the Office of Management in Budget, which falls under the purview of the White House. Thompson now answers to Chief of Staff Denis McDonough.

Republicans decried the move as stripping the autonomy of one of the government's most autonomous agencies and of politicizing the counting of Americans.

"Any attempt by the Obama administration to circumvent the census process for their political benefit will be met with fierce opposition, as this ill-conceived proposal undermines a constitutionally obligated process that speaks to the very heart of our democracy," California Rep. Darrell Issa wrote Obama in a February 2009 letter.

The document was co-signed by North Carolina Rep. Patrick McHenry.

Issa is chairman of the House Oversight and Government Reform Committee, and McHenry is one of 23 GOP members. Farenthold's panel falls under its authority.

"My subcommittee will be thoroughly investigating this issue and demanding answers from Census officials on allegations that the Census Bureau is changing the wording of survey questions used to determine our nation’s annual report on health insurance coverage," Farenthold told Newsmax.

Regarding Obamacare, the Census Bureau's changes come amid heavy criticism of the beleaguered healthcare law. HHS Secretary Kathleen Sebelius resigned on Friday, ending a stormy five-year tenure at the helm of the agency, which was marred by the disastrous rollout of the Affordable Care Act.

Obama nominated Sylvia Mathews Burwell, the OMB's current director, to replace Sebelius. Her confirmation must be approved by the Senate, but Republicans in both chambers of Congress have continued their calls for full repeal of the healthcare law.

"It's the worst piece of legislation that's been passed in at least the last half century — and it is the single biggest step in Europeanizing our country," Senate Minority Leader Mitch McConnell told Newsmax in an exclusive interview within hours of news circulating that Sebelius was quitting. "If the American people will give us the votes to do it, we intend to repeal it."

Before her resignation became public, Sebelius told Congress that 7.5 million Americans had signed up for coverage under Obamacare and that 11.7 million had been deemed eligible for Medicaid and the Children's Health Insurance Program.

The Obamacare open-enrollment period lasted from Oct. 1 to March 31. . The period was marked by several extensions — and the White House said just days before the final deadline that those who could not enroll in plans by then through the glitch-plagued HealthCare.gov website would have until the middle of this month to do so.

Regardless, the White House has not been able to say how many of the 7.5 million Americans had no health insurance beforehand or had lost policies since the enrollment period began — a continued attack by Republicans that the administration has not been able to determine the net effect of Obamacare.

"The health insurance data reported in September of this year will not be directly comparable to what was reported last September," Kathleen Thiede Call, a professor at the University of Minnesota School of Public Health, told the Times.

She was consulted by the Census Bureau on the revamped questionnaire.

“I am excited about the redesign of the survey," she added. "For the first time, we will be able to look at monthly changes in coverage over a 14- or 15-month period, which was not possible with the old version of the survey."